Evaluation of Marginal Microleakage and Depth of Penetration of Different Materials Used as Pit and Fissure Sealants: An In Vitro Study

The effect of preprocedural mouthrinses against COVID-19 before acid etching on the microleakage of a resin-based sealant in permanent molars: An in vitro experimental study

Aim

To determine whether rinsing with preprocedural mouthrinses against coronavirus disease before acid etching affects resin-based sealant microleakage.

Materials and Methods

A presented in vitro experimental study was performed on 15 extracted permanent third molars. Samples were randomly allocated into five groups: Group 1-distilled water (control); Group 2-1% hydrogen peroxide; Group 3-1.5% hydrogen peroxide; Group 4-0.5% povidone-iodine; and Group 5-1% povidone-iodine. After the teeth were immersed in the assigned mouth rinses for 60 s, they were sealed with Concise™ white sealant. Subsequently, the teeth were thermocycled for 500 cycles, immersed in 2% methylene blue solution for 24 h, and sectioned with two parallel cuts in the buccolingual direction. Sixty surfaces (12 surfaces in each group) were examined for microleakage under a 40× light microscope and scored as described by Zyskind et al. Welch's one-way analysis of variance test and the Games-Howell test were used to analyze the results at a significance level of P < 0.05 for all tests.

Results

The intergroup comparisons indicated that the 0.5% povidone-iodine group and the 1% povidone-iodine group had significantly higher microleakage compared with the control group. The 1% and 1.5% hydrogen peroxide groups demonstrated no significant difference in mean microleakage scores compared with the control group. There was no significant difference between the povidone groups and the hydrogen peroxide groups.

Conclusions

Preprocedural rinsing with 0.5% and 1% povidone-iodine before acid etching caused higher microleakage of resin-based sealant, while hydrogen peroxide rinsing gave comparable microleakage compared with the control group.

Penetration and Adaptation of the Highly Viscous Zinc-Reinforced Glass Ionomer Cement on Contaminated Fissures: An In Vitro Study with SEM Analysis

Objective: To evaluate the penetration and adaptation of highly viscous zinc-reinforced glass ionomer cement (ZRGIC), using a scanning electron microscope (SEM), when applied under various contaminated conditions on grooves and fissures of primary second molars. Materials and Methods: A total of 40 extracted human primary second molars were randomly assigned into five groups (8 teeth each), with different surface conditions (conditioned with 40% polyacrylic acid, dry condition, water contamination, saliva contamination, or saliva contamination and air-drying) on the occlusal surface before placement of zinc-reinforced highly viscous glass ionomer cement with the finger-press technique. After sectioning the teeth, they were subjected to SEM analysis, where four in each group underwent aging by thermocycling and the other four were without aging. ANOVA tests, post hoc analysis, and unpaired t-tests were used for statistical analyses. Results: There was a significant statistical difference in the sealant penetration in the non-aging group, but in the aging group, there was no significant statistical difference in the sealant penetration. On other hand, a significant statistical difference was found in the adaptation between all the groups (p < 0.05). Highly viscous zinc-reinforced glass ionomer fissure sealants have better fissure penetration and more intimate adaptation under fissures conditioned with 40% polyacrylic acid and dry surface fissures with no contamination. However, the best penetration and retention after aging were under contaminated fissures with a shiny layer of saliva. Conclusions: The ZRGIC is a highly viscous fluoride-releasing cement, effectively seals fissures by interfering with food lodgment and protecting teeth from caries. It is advisable to restore the fissures with the minimal technique of sensitive fluoride-releasing GIC, particularly in young, uncooperative children, rather than leaving a caries-prone environment.

Effect of nano-hydroxyapatite incorporation on fluoride-releasing ability, penetration, and adaptation of a pit and fissure sealant

BACKGROUND

Dental caries is one of the most common multifactorial oral diseases and can be prevented using pit and fissure sealants.

AIM

To evaluate the effect of nano-hydroxyapatite (nanoHAP) incorporation on fluoride-releasing ability, penetration, and adaptation of a pit and fissure sealant.

DESIGN

This was an in vitro study with two groups: conventional sealant and nanoHAP-incorporated sealant. Sealant penetration and adaptation were assessed using stereomicroscope and scanning electron microscope (SEM) (15 and 10 samples per group, respectively). Fluoride release was analyzed using ion-selective electrode (15 samples per group). The chi-square test was used to compare penetration and adaptation between the 2 groups, and an independent Student t test was used to compare fluoride release.

RESULTS

The nanoHAP group showed significantly more samples with no bubbles (P = .001) and no debris (P < .001). SEM analysis showed a significantly greater percentage of adequate fissures in the test group (P = .007). The fluoride release was significantly higher in test samples with p values of .001 and .016 on day 1 and day 60, respectively.

CONCLUSION

The incorporation of nanoHAP into the conventional pit and fissure sealant improved its penetration and adaptation properties along with fluoride release.

Glass Ionomer Sealant versus Fluoride Varnish Application to Prevent Occlusal Caries in Primary Second Molars among Preschool Children: A Randomized Controlled Trial

Fissure sealant is a recommended preventive measure on permanent molars, but its efficacy on primary molars in preschool children is still in doubt. Sodium fluoride varnish (NaFV) enhances remineralization and is effective in preventing caries in smooth surfaces, but limited information is available regarding its use on occlusal surfaces of primary molars. The present study aimed to compare the efficacy of glass ionomer sealant (GIS) versus topical application of 5% NaFV in preventing and arresting occlusal caries in primary second molars among preschool children. One calibrated examiner examined children aged 3-4 years for visible plaque index (VPI), decayed-missing-filled primary surface (dmfs) index, and extent of carious lesions by the International Caries Detection and Assessment System (ICDAS). Subjects with 1 or more primary second molars that were sound or with incipient lesions (ICDAS 0-1), with distinct visual enamel changes (ICDAS 2), or with localized enamel breakdown (ICDAS 3) were recruited. The children were randomly assigned to either NaFV group - application of 5% NaFV at 3-monthly intervals or GIS group - 1 single placement of GIS. A parental questionnaire was used to collect information on the children's sociodemographic background and oral health-related habits. Two blinded examiners conducted clinical examinations after 6 and 12 months to evaluate the development of occlusal caries and the retention of GIS. Negative binomial regression using generalized estimating equations was employed to adjust for the clustering effect and evaluate the influence of selected variables on the development of occlusal caries into dentin at 12 months. A total of 323 children with 1,159 primary second molars received the respective preventive measures at baseline. At 12 months, 280 children with 989 molars were evaluated. Caries had developed or progressed into dentin in 7.8% and 8.0% of the molars in the NaFV and GIS groups, respectively, with no significant difference between the groups (p = 0.913). The overall retention rates of GIS were 24.6% and 13.5% at 6 and 12 months, respectively. Regression analyses showed only baseline caries experience, and an ICDAS code had a significant association with occlusal caries progression. Quarterly NaFV application and single GIS placement showed similar effectiveness in the prevention of occlusal caries development among preschool children.

High-mobility group box protein-1 induces acute pancreatitis through activation of neutrophil extracellular trap and subsequent production of IL-1β

PURPOSE

The aim of this study is to evaluate acute pancreatitis (AP)-associated NET activation mediated by a novel inflammatory mediator (high-mobility group box protein-1 [HMGB1]) and proinflammatory cytokine responses.

METHODS

In this study, primary neutrophils, monocytes, and monocytic cell line Thp-1-derived macrophages were isolated and treated with HMGB1, lipopolysaccharide (LPS), adenosine triphosphate (ATP), and ATP + ATP inhibitor. The effects of HMGB1, ATP, and deoxyribonuclease (DNAse) were then examined for their in vivo effects using a newly established AP mouse model.

RESULTS

The mRNA and protein levels of inflammasome and interleukin IL-1β in cells, blood, and pancreatic tissues were examined. Within-cell nuclear DNA signal, cell-free DNA concentration, and pancreatic tissue damage were investigated. Our study showed that HMGB1 triggers NET formation in neutrophils and promotes the activation of inflammasome complexes (the NLR family, pyrin domain containing 3, and NLRP3; ASC; and caspase-1); therefore, the production of IL-1β is induced in human monocytes/macrophages. HMGB1 and NET cooperatively stimulate IL-1β processing in macrophages. Furthermore, the AP mouse model confirmed these HMGB1-mediated molecular mechanisms in vivo and indicated that HMGB1 is required for NET activation.

CONCLUSIONS

We found that NET inhibition reverses HMGB1-stimulated inflammasome activation and IL-1β production. HMGB1 thus leads to pancreatic injury through the activation of NET and subsequently induces IL-1β processing from neutrophils to pancreatic tissues. These findings demonstrate that HMGB1 and NET are new therapeutic targets for inflammation suppression in severe AP.